All viruses, including SARS-CoV-2, the virus causing Covid-19, mutate and change with time - that's how we end up with variants.
While the news is dominated by new cases of the latest virus strains, it's easy to lose track of what this actually means.
Here are the basics to keep you up to speed:
"Most changes have little to no impact on the virus’ properties," the World Health Organisation (WHO) explains on its official advice page.
"However, some changes may affect the virus’ properties, such as how easily it spreads, the associated disease severity, or the performance of vaccines, therapeutic medicines, diagnostic tools, or other public health and social measures."
Initially, these variants were named after the country or region where they were originally discovered, but this is no longer the case.
The names were changed to avoid the stigma around new variants being linked to certain places and the WHO said that a country may be more willing to report a newly discovered variant if it is not given the name of that country, which is where the Greek alphabet comes in.
As such, the WHO classifies these variants in two separate categories, Variants of Concern (VOC) and Variants of Interest (VOI).
Variants of Interest (VOI)
These are defined as a variant:
- With genetic changes that are predicted or known to affect virus characteristics such as transmissibility, disease severity, immune escape, diagnostic or therapeutic escape; and
- Identified to cause significant community transmission or multiple Covid-19 clusters, in multiple countries with increasing relative prevalence alongside an increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.
Currently, those are:
Eta - discovered in several countries, December 2020
Iota - discovered in the United States, November 2020
Kappa - discovered in India, October 2020
Lambda - discovered in Peru, December 2020
Variants of Concern (VOC)
To be considered a Variant of Concern by the WHO, the variant has to meet the definition of a VOI and, through a comparative assessment, it has to be proven that it is associated with one or more of the following changes at a degree of global public health significance:
- Increase in transmissibility or detrimental change in Covid-19 epidemiology; or
- Increase in virulence or change in clinical disease presentation; or
- Decrease in the effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.
Currently, those are:
Alpha - discovered in the UK, September 2020
Beta - discovered in South Africa, May 2020
Gamma - discovered in Brazil, November 2020
Delta - discovered in India, October 2020
While the Alpha variant already caused Belgium to briefly close its borders to the UK during the 2020 Christmas period, and the Beta and Gamma mutations saw the country banning all travellers from South Africa and Brazil, it is the Delta variant that is currently worrying experts.
Earlier this week, experts announced that Delta is currently the dominant strain in Belgium, as it accounts for over 50% of all Covid-19 infections in the country.
Its higher infection rate has caused cases to go up across Europe in the last few weeks and is also one of the reasons behind the recent sharp increase in Belgium's infection figures, but there is no reason to panic yet, according to virologist Steven Van Gucht.
While the increase in the number of infections may also translate into an increase in the number of hospital admissions, he expects it to be less pronounced as most high-risk people groups have already been vaccinated.
In the UK, where the Delta variant has been dominant for several weeks, the number of infections increased quickly, but the number of hospital admissions remained relatively low in comparison.
However, that did not stop Belgium from imposing a travel ban on all travellers from the country in mid-June, in an attempt to keep the variant out.
Additionally, travel restrictions or not, vaccination is and remains the only true solution, according to the European Medicines Agency (EMA), which recently stated that "it seems that the four vaccines approved in the EU protect against all virus strains circulating in Europe, including the Delta variant.”
As of Wednesday 7 July, 79.8% of the adult population in Belgium has received its first shot of a coronavirus vaccine, and 47,2% has been fully vaccinated, according to the latest figures by the Sciensano national health institute.
Maïthé Chini contributed to this story